Method of and apparatus for forming packages with tear tabs

ABSTRACT

In the production of packages by the form-fill-seal technique, a tear tab is heat-sealed to each package for tearing an opening in the package. The packages are made by forming a web of heatsealable packaging material into tubing around a mandrel, and forming package end seals across the tubing spaced at package length intervals by means of end sealers which move up and down below the lower end of the mandrel through a package length stroke and which act to feed the tubing downwardly off the lower end of the mandrel one package length increment on each downstroke. A tear tab is heat-sealed to the tubing on the mandrel during each dwell interval of the tubing between successive downstrokes, the tabs thus being spaced at package length intervals on the tubing, one for each package ultimately formed.

United States Patent Pringle, Jr. et al.

[54] METHOD OF AND APPARATUS FOR FORMING PACKAGES WITH TEAR TABS Y [72] Inventors: Frank E. Prlngle, Jr.; George Allan West, both of Sheboygan; Walter H. Vogel, Plymouth; Richard W. Salranski; Frederick R. Drake, both of Sheboygan, all of Wis.

[73] Assignee: Hayssen Manufacturing Company,

Sheboygan, Wis,

22 Filed: July 2,1970

21 Appl. No.: 51,775

[52] US. Cl ..53/l4, 53/l33 [5 1] Int. Cl. ..B65b 61/18 [58] Field of Search ..53/l4, 28, 133, l80, I82;

[ 56] References Cited UNITED STATES PATENTS 3,545,161 12/1970 Hoshino etal ..53/28X FOREIGN PATENTS OR APPLICATIONS 789,383 7/l968 Canada ..229/66 151 3,681,890 51 Aug. 8, 1972 Primary Examiner-Theron E. Condon Assistant Examiner-Eugene F. Desmond Attomey-Koenig, Senniger, Powers and beavitt ABSTRACT In the production of packages by the forrn-fill-seal technique, a tear tab is heat-sealed to each package for tearing an opening in the package. The packages are made by forming a web of heat-scalable packaging material into tubing around a mandrel, and forming package end seals across the tubing spaced at package length intervals by means of end sealers which move up and down below the lower end of the mandrel through a package length stroke and which act to feed the tubing downwardly off the lower end of the mandrel one package length increment on each downstroke. A tear tab is heat-sealed to the tubing on the mandrel during each dwell interval of the tubing between successive downstrokes, the tabs thus being spaced at package length intervals on the tubing, one for each package ultimately formed.

5 Claims, 16 Drawing Figures P'ATENTEU nus 8 I972 SHEET 2 OF 5 MI I37] ETLLCF 5 PATENTEDAus 8 m2 PATENTEmus 8 m2 SHEET 5 [IF 5 NFN METHOD OF AND APPARATUS FOR FORMING PACKAGES WITH TEAR TABS BACKGROUND OF THE INVENTION This invention relates to methods of and apparatus for forming packages, and more particularly to methods of and apparatus for making packages of plastic film by the form-fill-seal technique with each package provided with means for easy opening thereof.

The invention is particularly concerned with the provision of tear tabs on packages being made from a heat-scalable plastic film web by the form-fiIl-seal technique, in which the web is formed into tubing, the tubing is intermittently advanced in package length increments with a dwell interval between successive feed cycles, and transverse seals constituting package end seals are formed across the tube at said package length intervals, the product with which the packages are to be filled being delivered endwise internally of the tubing. By a "tear tab" we mean one which is sealed to the package and which, when torn away from the package, tears an opening in the package. Reference may be made, for example, to U.S. Pat. No. 3,098,60l showing a package having such a tear tape extending across the package for tearing a slit in the package extending across the package. This is to be distinguished from a tab covering a hole in the package, as shown for example in U.S. Pat. No. 3,287,878.

SUMMARY OF THE INVENTION Among the several objects of the invention may be noted the provision of a method of and apparatus for applying tear tabs to packages made by the form-fillseal technique as above described, the tab being adapted to be torn away from the package to provide an opening for pouring out the contents of the package; the provision of such a method and apparatus for providing tabs of heat-scalable material heat-sealed to packages of heat-scalable material, such as polyethylene; the provision of such a method and apparatus adapted to apply the tabs to the packages at a corner thereof with the tab extending lengthwise of the package; and the provision of such a method and apparatus which avoids interference with the formation of the web of packaging material into tubing in the course of the form-fill-seal operation.

In general, the method is utilized in the production of filled packages by the form-fill-seal technique in which a web of heat-scalable material is formed into tubing and the tubing is intermittently advanced in package length increments with a dwell interval between successive feed cycles, and in which transverse seals constituting package end seals are formed across the tubing at package length intervals, the product with which the packages are to be filled being delivered endwise internally of the tubing. It involves the steps of applying a length of tab material which is heat-sealable at least on one face thereof to the outside of each package length increment of the tubing with the heat-scalable face of the tab material facing the tubing, and heat-sealing the said length of tab material to the tubing over a portion only of the area of the said length of tab material, thereby to provide a tear tab on each package with the tab having a free portion adapted to be grasped and pulled to tear an opening in the package where the tab is sealed to the package. The apparatus is applied to a form-fiIl-seal machine operating as above-noted and generally comprises means for applying a length of tab material which is heat-sealable on at least one face thereof to the outside of each package length increment of the tubing with the heat-scalable face of the tab material facing the tubing, and means for effecting heat-sealing of the said length of tab material to the tubing over a portion only of the area of the said length of tab material to provide a tear tab such as described on each package. Each length of tab material is cut from a continuous length of tape, the tape being fed toward the tubing from a roll of tape and forward in the direction of the length of the tubing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of a form-filI-seal packaging machine equipped with apparatus of this invention for applying tear tabs to packages being made by the machine;

FIG. 2 is a side elevation of the machine shown in FIG. 1, with parts broken away;

FIG. 3 is a view in front elevation illustrating the application of a tab to tubing in the FIG. 1 machine and the formation of the tubing into a package;

FIG. 4 is a side elevation of FIG. 3;

FIG. 5 is an enlarged horizontal section on line 5-5 of FIG. 4;

FIG. 6 is an enlarged front elevation of the apparatus for applying tear tabs to the tubing, with parts broken away and shown in section;

FIG. 7 is a view in elevation of the left end of FIG. 6;

FIG. 8 is a horizontal section on line 8-8 of FIG. 6;

FIG. 9 is an enlarged plan of the tear tab applying apparatus, with parts broken away and shown in section;

FIG. 10 is a vertical section on line 10-10 of FIG. 9;

FIG. 11 is a view similar to FIG. 6 showing a moved position of parts and with parts broken away and shown in section;

FIG. I2 is a view of the top of a filled package, showing the tab thereon;

FIG. 13 is an idealized front elevation of the corner portion of the package with the tab;

FIG. 14 is a view corresponding to FIG. 13 with the tab torn away;

FIG. 15 is an enlarged section on line l5l5 of FIG. 13; and

FIG. 16 (sheet 2) is a fragmentary view similar to FIG. 11 with parts broken away and shown in section and in a moved position.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, first more particularly to FIGS. 1 and 2, there is indicated at l a vertical formfiIl-seal packaging machine of a type on which the method of this invention may be carried out and to which apparatus of this invention may be applied. The machine, as shown, is particularly for forming plastic packages of milk and has a liquid dispenser or tiller 3 for this purpose. It will be understood, of course, that the present invention is applicable to the machine I or other suitable form-fiIl-seal machines for forming packages of many different products. Generally, the packaging machine 1 comprises a base 5 and a frame 7 extending up from the base. At 9 is indicated a tubular cylindrical mandrel which is mounted in vertical position at the front of the frame 7. A supply roll R of a web W of suitable heat-scalable packaging material such as polyethylene is mounted at 11 in the frame. The web W is fed from the roll R around guide rollers 12 and 13 to the upper end of the mandrel 9, being formed into tubing T around the mandrel as will be readily understood by those skilled in the art, the tubing being completed by formation thereof with a longitudinal seam such as indicated at L in FIG. I by means of a longitudinal sealer 14 located in front of the mandrel. At 15 is indicated a carriage adapted to reciprocate vertically upward and downward toward and away from the lower end of the mandrel. This carries end seal bars indicated at 17 (see also FIGS. 3-5) adapted, on each downward stroke of the carriage, to close on the tubing T below the lower end of the mandrel and to form a transverse seal across the tubing while pulling down one package length off the lower end of the mandrel. The transverse seal forms an upper end seal for the package being completed and a lower end seal for the next package, and bars 17 may have cutter or severing means associated therewith for cutting across the tubing midway of the transverse seal to separate the completed package from the next package. The bars 17 then open, and the carriage then moves upward for the next cycle, the tubing dwelling in place during the upward movement of the carriage. It will be understood by those knowledgeable in the art that other means may be employed to obtain motion (advance) of the tubing in place of the aforementioned carriage.

The dispenser or filler 3 is shown as comprising a product supply tube 19 which extends vertically downward within the mandrel from a product supply reservoir 21 to the lower end of the mandrel (which is open). At the lower end of the tube 19 is a filler valve V actuated via a rod 65 (see FIG. 3) by an air cylinder 79 on top of the reservoir. Reference may be made to the copending coassigned US. application Ser. No. 32,841, filed Apr. 29, 1970, for full details of the filler 3. It will be understood that other suitable fillers may be used.

The packaging machine 1 functions as above noted to form the web W of heat-scalable flexible sheet packaging material into tubing T around the mandrel 9 and intermittently to feed this tubing downwardly in package length increments off the lower end of the mandrel 9 (on each downstroke of the carriage 15 carrying the seal bars 17) with a dwell interval between successive feed cycles (these dwell intervals occurring on each upstroke of the carriage 15 and seal bars 17). The seal bars 17 form transverse seals constituting package end seals across the tubing at package length intervals longitudinally of the web. The product (e.g., milk) with which the packages formed by the machine are to be filled is delivered downwardly through supply tube 19 internally of the tubing T to the lower end of the tubing T during intervals between formation of successive end seals by appropriate operation of valve V via rod 65 by air cylinder 79.

In accordance with this invention, the machine I is provided with apparatus indicated generally at 21 for applying a length of tab material which is heat-scalable on at least one face thereof to the outside of the tubing T with the heat-scalable face of the tab material facing the tubing, and heat-sealing the said length of tab material to the tubing over a portion only of the area of said length of tab material to provide a tear tab on each package having a free portion adapted to be grasped and pulled to tear an opening in the material of the package where the tab is sealed to the package.

FIGS. 3, 4 and [2 illustrate a package P made as above noted. As shown, the package has a front wall 23, a back wall 25 including the longitudinal seam L, these walls being joined at integral side edge folds 27 and 29, and end seals 31 and 33. In FIGS. 3 and 4, 31 is the lower end seal, and in FIGS. 12-14 the package is shown turned end-for-end with 31 as the upper end seal. A tear tab 35 is heat-sealed to the package on a V- shaped seal 37 adjacent one comer (the lower right corner as shown in FIG. 4 and the upper left corner as shown in FIG. 12) of the package. This tab, as shown in FIG. 12, extends longitudinally of the package downwardly from the end seal 31 (here the upper end seal). The V-shaped seal 37 has its apex 370 on the fold, one side 37!: thereof extending upward toward end seal 31 in the front wall 23 and its other side 37c extending upward toward end seal 31 in the back wall The apparatus 21 comprises a frame generally designated 41 which is mounted on frame 7 of the machine 1 at one side of the mandrel 9 (at its right side as shown in FIG. 1) and somewhat above the lower end of the mandrel. The frame 41 comprises two spaced vertical side plates each designated 43, a top plate 45, an end plate 47, and an upper shelf 49 and a lower shelf 51 spanning the side plates below the top plate. On the outside of one of the side plates (the back side plate) is a C-clamp 53 (see particularly FIG. 9) which straddles a vertical bar 55 of a bracket 57 which is mounted on the machine frame 7 as indicated at 59. The clamp 53 has a clamp screw 61 by means of which the frame 41 is clamped in vertically adjusted position on the vertical bar 55. The frame is located in the vertical diametrical plane of the mandrel which is at 90 to the vertical diametrical plane of the longitudinal seal L of the tubing T with its open end (its end opposite the back plate 47) closely adjacent the mandrel. Its open end is referred to as its forward end.

A horizontal shaft 63 is journalled in a pair of bearings 65 on the outside of the end plate 47 of the frame 41. A rocker lever 67 has a hub formation 69 at the bottom thereof intermediate its ends secured on one end of the shaft 63 (its back end toward frame 7). A crank arm 71 is clamped as indicated at 73 on the shaft 63 between the bearings 65. A holder 75 for holding a roll 77 of tape 78 of tab-forming material has its axis extending laterally from the lever 67 in the direction away from machine frame 7 adjacent one end of the lever (which may be referred to as its rearward end). The tape 78 may be, for example, a tape of cellophane with a layer of polyethylene on one face thereof (which would be the outer face of the tape in the roll 77 as herein shown). The roll, as shown in FIG. 9, is frictionally mounted on the arbor. At its other end (its forward end), lever 67 has a finger 81 extending laterally in the direction away from machine frame 7.

Secured on the forward face of finger 81 is a tape guide or shoe 83 for guiding tape from the roll 77 in downward direction. This guide comprises an elongate plate extending from a point above finger 81 to a point well below finger 81 and having a tape guide channel 85 in its outside face extending from its upper to its lower end, with a curved entry 87 to the channel at its upper end. The guide 83 is secured to the finger by screws 89 extending through a block 91 and a lateral tongue 93 on the guide and threaded in the finger 81, and this block carries a spring finger 95 for holding the tape 78 down in the channel 85.

The lever 67 is shown in FIG. 6 in what may be referred to as a first position wherein guide 83 is in a lowered position. An air cylinder 97 is provided for rocking the lever 67 between this first position and a second position such as shown in FIGS. 11 and 16 wherein the guide 83 is in a raised position. The air cylinder has one end pivoted as indicated at 99 in a clevis 101 extending down from the bottom of the lower shelf 51 adjacent the forward end of the frame 41, and has a piston rod 103 extending from its other end toward the back end of the frame 41. Rod 103 has a connector 105 at its rearward end adjustable lengthwise of the rod and having a pin 107 received in a slot 109 in the crank arm, the adjustment permitting positioning of the pin at various points in the slot 109 (nearer or farther from the axis of shaft 63) for varying the stroke of the crank arm 71 and hence the lever 67. The back plate 47 has an opening 111 for passage of the rod and the connector 105. Piston rod 103, when extended, holds lever 67 in its stated first position of FIG. 6 and when retracted swings the lever 67 in clockwise direction as viewed in FIG. 6 to its stated second position of FIGS. 11 and 16.

The top plate 45 of frame 41 terminates short of the forward edges of the side plates 43, and the guide 83, when lowered, extends down between the forward end of the top plate and a vertical shear blade 1 13 spanning the forward edges of the side plates 43 at the upper ends of these edges. Provision is made for vertical adjustment of this blade as indicated at 115 in FIG. 7 to register its lower edge 1 17, which is beveled as shown, with a cutter blade 119 mounted for reciprocation in the compartment 121 in frame 41 between the upper shelf 49 and the top plate 45. The cutter blade is carried by a carriage or slider 123 slidable in compartment 121, the blade being secured to the bottom of a bar 125 extending transversely of slider 123 in a recess therein and pivoted on a pin 127 extending through the bar having its ends received in holes in the sides of the slider. A spring 129 biases the blade to swing in clockwise direction as shown in FIG. 6 about the axis of pin 127 to a raised position of its forward end, which is angled as appears in FIG. 9. An air cylinder 129 is mounted in compartment 121, having a piston rod 131 extending from the piston (now shown) therein to a connection at 133 with the slider 123. The arrangement is such that, on extension of the piston rod 131, the cutter blade 119 is driven forward (toward the left as viewed in FIG. 6), from its retracted position of FIG. 6, the on retraction of the piston rod, the cutter blade is pulled back to its retracted position. The blade is driven forward through a cutting stroke with the guide 83 raised (see FIG. 16), the blade thus passing under the guide 83 and its cutting edge acting in conjunction with the lower edge 117 of blade 113 to shear off tape 78 extending down below the lower edge 117 of blade 1 13.

An air cylinder 135 is mounted on the lower shelf 51 in the compartment 137 between the upper shelf 49 and the lower shelf. A piston rod 139 extends from the piston (not shown) in cylinder 135 through the forward end of the cylinder and has its forward end secured as indicated at 141 to a carriage or slider 143 slidable in compartment 137. A pair of rods 145 slidable in bores 147 at opposite sides of the slider 143 carry a clamp jaw 149 at their forward ends. The clamp jaw has a resilient (rubber) facing 15], and a circular central opening 153. Springs bias the clamp jaw 149 forward relative to the slider 143 to a limit determined by engagement of nuts 157 on the rear ends of the rods 145 with the rear end of the slider. The clamp jaw 149 is adapted to yield back toward the slider 143 against the bias of these springs. An elongate cylindrical heatseal member 159 is threaded in a central opening 16] in the forward end of the slider 143 and extends forward therefrom in coaxial alignment with the opening 153 in the clamp jaw 149. This member 159, which is of somewhat smaller diameter than opening 153, is tubular and contains an electrical resistance heater element 163 (see FIG. 16) supplied with current via wiring 165 having a coil section (not shown) accommodating the reciprocation of the slider 143. At its forward end, member 159 has a formation 169 for making a desired heat-seal pattern shown in this instance as a V- formation for making the V-shaped seal referred to previously. This V-formation is inverted, for a reason that will appear. Conduit for the wiring to the heater element is indicated at 171 in FIGS. 9 and 10. Operation is as follows:

On each downstroke of the end sealer carriage 15 carrying the end sealers 17, the end sealers 17 are closed on the tubing T (as shown in FIG. 3) and, while pulling the tubing T downward one package length increment, act to form a transverse seal across the tubing (forming an end seal 33 for the package being completed and an end seal 31 for the next package to be formed), and the tubing is cut generally midway between the upper and lower edges of the transverse seal to separate the completed package P from the tubing. At the end of their downstroke, the end sealers 17 open, and the carriage 15 and the end sealers move upward through a return stroke, during which interval the tubing T dwells, and the product with which the packages are to be filled is delivered into the lower end of the tubing via pipe 19 extending internally of the tubing within the mandrel 9.

During the downward feed of the tubing T, both sliders 123 and 143 are in their retracted position as shown in FIGS. 6 and l 1 so that the cutter blade 119 is in its retracted position and the clamp jaw 149 and heat-seal member 159 are in their retracted position of FIGS. 6, 8 and 11.

As shown in FIG. 11, the tape guide 83 is in its raised retracted position, with an end portion 78c of tape 78 extending down below the lower end of the guide 83 (as a result of the previous cycle of operation). While the carriage 15 is moving downward with the end sealers I7 closed and thereby moving the tubing T downward, cylinder 97 is actuated to extend the piston rod 103 and thereby rock the lever 67 in counterclockwise direction as viewed in FIG. 11 to swing the guide 83 down to its lowered position of FIG. 6. The tape 78, being held clamped against the guide 83 by the spring hold-down finger 95, moves down with the guide 93, and the end portion 78e of the tape is thus brought down into position between the clamp jaw [49 and the tubing T on the mandrel 9.

When the downward feed of thetubing T by the end sealers 17 has been completed, and during the ensuing dwell interval of the machine cycle, cylinder 135 is actuated to drive the slider 143 carrying the clamp jaw 149 and the heat-seal member 159 forward (i.e., toward the mandrel 9). The clamp jaw I49 engages the end portion 78c of the tape 78 and clamps it against the tubing T (utilizing the mandrel 9 as a back-up) and on continued forward movement of the slider 143, the heat-seal member 159 moves forward through the opening 153 in the clamp jaw I49 and the V-formation 169 at the forward end of the member 159 engages the end portion 79c of the tape 78 and heat-seals it to the tubing T, forming the V-shaped seal 37 referred to previously and shown in FIGS. 12 and 13.

While the end portion 78e of the tape 78 is held clamped against the tubing T by the rubber face 151 of the clamp jaw 149 and while it is being sealed to the tubing T by the member 159, the cylinder 97 is operated to retract the piston rod 103 and rock the lever 67 clockwise as viewed in FIG. 6 to raise the tape guide 83 to its FIG. 16 retracted position. Since the end of the tape 78 is held clamped by clamp jaw 149, a length of tape 78 corresponding to the throw of the guide 83 is unwound from the tape roll 77, and the guide 83 stops in its raised position with a length of tape extending from the lower end of the guide 83 down to the clamp jaw 149 in position for being cut by the cutter blade 119. It will be observed that, on raising the guide 83 with the lower end of the tape clamped by the jaw 149, the loop of the tape between the roll 77 and the clamped end of the tape is enlarged, thereby unwinding the said length of tape from the roll 77. It will also be noted that this is effected, as is desirable, without strain on the sealed area of the tape, since the tape is clamped to the tubing T by the rubber facing 151 of jaw 149 all around the inverted V sealing formation 169. The cutter blade cylinder 129 is then actuated to drive the cutter blade 119 forward, and the tape is cut off at the level of the lower edge [17 of the fixed shear blade 113 (see FIG. 16), leaving a tab 35 extending away from the sealed region of the tape, and leaving an end portion 78c of the tape extending away from the lower end of the guide ready for the next cycle.

From the above, it will appear that a tear tab 35 is heat-sealed to the tubing T on the mandrel 9 during each dwell interval of the tubing T between successive downstrokes of the end sealing bars 17, the tabs 17 thus being spaced at package length intervals on the tubing, one for each package being formed. Each tab is applied in position to lie at a corner of a package with one end spaced from the respective end seal and with the tab extending lengthwise of the package away from that end seal. Each tab is heat-sealed to the outside of the package by the V-shaped seal 37 as herein illustrated, and has a free end portion beyond the seal adapted to be grasped and pulled to tear an opening in the package such as indicated at 0 in FIG. 14. The sealing inherently provides lines of weakness in the package material along the outline of the seal, this outline being a V as herein illustrated. It will be understood, however, that seal formations other than a V may be used. With the tab formed of a material such as the cellophane/polyethylene laminate above mentioned, it is insured that the package tears and not the tab. The tab length may be adjusted by adjustment of the stroke of lever 67.

It will be noted that the tabs are applied to the tubing T, rather than to the web W before it is formed into the tubing. This avoids interference with the formation of the web into the tubing, such as would tend to occur if the tabs were applied to the web W in the flat before it reached the mandrel 9. It also enables the tabs to be applied without difficulty near the end seals, as is desirable in many instances. it will be understood that in referring to the tabs as being applied to the tubing it is intended to cover their application to the tubing before the longitudinal seal L is formed to complete the for mation of the tubing, as well as their application to the tubing after the longitudinal seal has been formed.

In view of the above, it will be seen that the several objects of the invention are achieved and other advan tageous results attained.

As various changes could be made in the above constructions and methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the ac companying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. In the production of filled packages by the formfill-seal technique in which a web of heat-scalable material is formed into tubing and the tubing is intermittently advanced in package length increments with a dwell interval between successive feed cycles, and in which transverse seals constituting package end seals are formed across the tubing at package length intervals, the product with which the packages are to be filled being delivered endwise internally of the tubing, the steps of applying a length of tab material which is heat-scalable at least on one face thereof to the outside of each package length increment of the tubing with the heat-scalable face of the tab material facing the tubing, and heat-sealing the said length of tab material to the tubing over a portion only of the area of the said length of tab material, thereby to provide a tear tab on each package with the tab having a free portion adapted to be grasped and pulled to tear an opening in the package where the tab is sealed to the package, each said length of tab material being cut from a continuous length of tape, the tape being fed toward the tubing from a roll of the tape and forward in the direction of the length of the tubing, the end portion of the tape being cut off to form the said length of tab material, the said end portion of the tape being clamped against the tubing and heat-sealed thereto during the dwell interval of the tubing between successive feed cycles, the said end portion of the tape being cut off after it has been heat-sealed to the tubing, the cut-off being spaced from the seal, the feed of the tape being effected by enlarging a loop in the tape between the clamped lower end portion of the tape and the roll of tape.

2. In a form-fill-seal packaging machine in which a web of heat-scalable flexible sheet packaging material is formed into tubing and the tubing is intermittently advanced in package length increments with a dwell interval between successive feed cycles, transverse seals constituting package end seals being formed across the tubing at said package length increments, the product with which the packages formed by the machine are to be filled being delivered endwise internally of the tubing, means for applying a length of tab material which is heat-scalable on at least one face thereof to the outside of each package length increment of the tubing with the heat-scalable face of the tab material facing the tubing, and means for effecting heat-sealing of the said length of tab material to the tubing over a portion only of the area of the said length of tab material to provide a tear tab on each package having a free portion adapted to be grasped and pulled to tear an opening in the package where the tab is sealed to the package, said means for applying said length of tab material including means for cutting said length from a continuous length of tape, and further comprising means for feeding the tape toward the tubing from a roll of the tape and forward in the direction of the length of the tubing, said cutting means being operable to cut off the end portion of the tape to form the said length of tab material, said applying means further comprising means for clamping the said end portion of the tape against the tubing and heat-sealing said end portion of the tape to the tubing during the dwell interval of the tubing between successive feed cycles, the cutting means being located to cut the tape a sufficient distance from the seal to provide the said free portion of the tab adapted to be grasped and pulled, and being operable after the said end portion of the tape has been heat-sealed to the tubing, said feeding means comprising means for enlarging a loop in the tape between the clamped end portion of the tape and the roll of tape.

3. ln a form-fill-seal packaging machine having means around which a web of heat-scalable flexible sheet packaging material is formed into tubing and having vertically reciprocating end sealer bars for forming transverse seals constituting package end seals across the tubing at package length increments, said bars closing at the upper end of their stroke and pulling the tubing down one package length on each downstroke, and opening for their upstroke, the tubing dwelling during the upstroke, the product with which the packages formed by the machine are to be filled being delivered to the lower end of the tubing during intervals between the formation of successive end seals, means for applying tear tabs to the tubing at package length increments so that each package has a tear tab, said applying means comprising a lever pivoted intermediate its ends for rocking movement with one end of the lever constituting its inner end adjacent the tubing, means at the outer end of the lever for supporting a roll of tab-forming tape which is heat-scalable at least on one face thereof, means at the inner end of the lever for guiding the tape forward adjacent the tubing with an end portion of the tape extending beyond said guide means, means for rocking the lever between a first position wherein the guide means is advanced and a second position wherein the guide means is retracted, means for clamping said end portion of the tape against the tubing and heat-sealing it to the tubing, and means for cutting off said end portion of the tape.

4. In a form-fill-seal packaging machine as set forth in claim 3, said clamping and heat-sealing means comprising a carriage movable toward and away from the tubing, a clamp jaw for clamping said end portion of the tape against the tubing, said jaw being carried by the carriage for movement relative to the carriage toward and away from the carriage, means biasing the jaw to an extended position away from the carriage, said jaw having an opening therein and being yieldable back toward the carriage against the bias, and a heatseal member carried by the carriage in line with said opening, the forward end of said member being engageable with the tubing via said opening on yielding back of said jaw relative to the carriage against the bias.

5. In a form-fill-seal packaging machine as set forth in claim 4, said cutting means comprising a fixed shear blade spaced from said jaw, and a movable cutter blade cooperable with said fixed blade to cut the tape spaced from said jaw. 

1. In the production of filled packages by the form-fill-seal technique in which a web of heat-sealable material is formed into tubing and the tubing is intermittently advanced in package length increments with a dwell interval between successive feed cycles, and in which transverse seals constituting package end seals are formed across the tubing at package length intervals, the product with which the packages are to be filled being delivered endwise internally of the tubing, the steps of applying a length of tab material which is heat-sealable at least on one face thereof to the outside of each package length increment of the tubing with the heat-sealable face of the tab material facing the tubing, and heat-sealing the said length of tab material to the tubing over a portion only of the area of the said length of tab material, thereby to provide a tear tab on each package with the tab having a free portion adapted to be grasped and pulled to tear an opening in the package where the tab is sealed to the package, each said length of tab material being cut from a continuous length of tape, the tape being fed toward the tubing from a roll of the tape and forward in the direction of the length of The tubing, the end portion of the tape being cut off to form the said length of tab material, the said end portion of the tape being clamped against the tubing and heat-sealed thereto during the dwell interval of the tubing between successive feed cycles, the said end portion of the tape being cut off after it has been heat-sealed to the tubing, the cut-off being spaced from the seal, the feed of the tape being effected by enlarging a loop in the tape between the clamped lower end portion of the tape and the roll of tape.
 2. In a form-fill-seal packaging machine in which a web of heat-sealable flexible sheet packaging material is formed into tubing and the tubing is intermittently advanced in package length increments with a dwell interval between successive feed cycles, transverse seals constituting package end seals being formed across the tubing at said package length increments, the product with which the packages formed by the machine are to be filled being delivered endwise internally of the tubing, means for applying a length of tab material which is heat-sealable on at least one face thereof to the outside of each package length increment of the tubing with the heat-sealable face of the tab material facing the tubing, and means for effecting heat-sealing of the said length of tab material to the tubing over a portion only of the area of the said length of tab material to provide a tear tab on each package having a free portion adapted to be grasped and pulled to tear an opening in the package where the tab is sealed to the package, said means for applying said length of tab material including means for cutting said length from a continuous length of tape, and further comprising means for feeding the tape toward the tubing from a roll of the tape and forward in the direction of the length of the tubing, said cutting means being operable to cut off the end portion of the tape to form the said length of tab material, said applying means further comprising means for clamping the said end portion of the tape against the tubing and heat-sealing said end portion of the tape to the tubing during the dwell interval of the tubing between successive feed cycles, the cutting means being located to cut the tape a sufficient distance from the seal to provide the said free portion of the tab adapted to be grasped and pulled, and being operable after the said end portion of the tape has been heat-sealed to the tubing, said feeding means comprising means for enlarging a loop in the tape between the clamped end portion of the tape and the roll of tape.
 3. In a form-fill-seal packaging machine having means around which a web of heat-sealable flexible sheet packaging material is formed into tubing and having vertically reciprocating end sealer bars for forming transverse seals constituting package end seals across the tubing at package length increments, said bars closing at the upper end of their stroke and pulling the tubing down one package length on each downstroke, and opening for their upstroke, the tubing dwelling during the upstroke, the product with which the packages formed by the machine are to be filled being delivered to the lower end of the tubing during intervals between the formation of successive end seals, means for applying tear tabs to the tubing at package length increments so that each package has a tear tab, said applying means comprising a lever pivoted intermediate its ends for rocking movement with one end of the lever constituting its inner end adjacent the tubing, means at the outer end of the lever for supporting a roll of tab-forming tape which is heat-sealable at least on one face thereof, means at the inner end of the lever for guiding the tape forward adjacent the tubing with an end portion of the tape extending beyond said guide means, means for rocking the lever between a first position wherein the guide means is advanced and a second position wherein the guide means is retracted, means for clamping said end portion of the tape against the tubinG and heat-sealing it to the tubing, and means for cutting off said end portion of the tape.
 4. In a form-fill-seal packaging machine as set forth in claim 3, said clamping and heat-sealing means comprising a carriage movable toward and away from the tubing, a clamp jaw for clamping said end portion of the tape against the tubing, said jaw being carried by the carriage for movement relative to the carriage toward and away from the carriage, means biasing the jaw to an extended position away from the carriage, said jaw having an opening therein and being yieldable back toward the carriage against the bias, and a heat-seal member carried by the carriage in line with said opening, the forward end of said member being engageable with the tubing via said opening on yielding back of said jaw relative to the carriage against the bias.
 5. In a form-fill-seal packaging machine as set forth in claim 4, said cutting means comprising a fixed shear blade spaced from said jaw, and a movable cutter blade cooperable with said fixed blade to cut the tape spaced from said jaw. 